Both obesity and gastro-esophageal reflux disease (GERD) are known risk factors for cancer of the esophagus. Now Australian scientists have done a study to measure the relative risks from each risk factor, and published their findings in the medical journal Gut. They examined the records of 367 patients with cancer of the esophagus or the gastro-esophageal junction (a further 426 patients), and compared their findings with those from 1580 people from a population register, matched for age and gender.

For people who were obese but didn't have GERD, the risk of esophageal cancer was 6 times that of people who were not obese. But for people with GERD but who weren't obese, the risk of esophageal cancer was 5 times greater than for those without GERD. And for those who were obese and had GERD, the risk was 16 times greater. Similar, but slightly smaller, associations were found for the risk of gastro-esophageal junction cancers. Inclusion of smoking as a risk factor didn't alter the findings with respect to obesity and GERD to a relevant extent, although high-level smokers did have significantly higher risks of cancer than never-smokers.

It seems clear that a finding of obesity and GERD together would be a serious reason for someone to revise their lifestyle; losing a lot of weight would probably remove two risk factors for cancer and lead to a more enjoyable life altogether.